Clamping device for force responsive elements



y 1951 H... E. OWEN 2,560,366

CLAMPING DEVICE FOR FORCE RESPONSIVE ELEMENTS Filed Dec. 30, 1947Patented July 10, 1951 CLAMPIN G DEVICE FOR FORCE RESPONSIVE ELEMENTSHerbert E. Owen, Tulsa, Okla., assignor to Standard Oil DevelopmentCompany, a corporation of Delaware- Application December 30, 1947,Serial No. 794,617

1 Claim. 1

The present invention is directed to devices utilizing a mass includedin a moving system responsive to a force to be measured. In particularthe invention relates to a clamping mechanism for holding said massstationary when the system is not in operation and for the operation ofthe clamping mechanism from a remote position. The invention is ofspecial application in the design of underwater gravity meters.

In systems of the general type referred to above, such as gravitymeters, seismic pickups, and the like, a mass is suspended as freely aspossible in a moving system and means are provided for measuring themovement of the mass in response to a force to be measured. Thesesystems are necessarily of an extremely delicate nature if they are topossess the desired sensitivity. Consequently said systems cannot betransported safely unless some means is provided for clamping the movingsystem in a stationary position during transportation. As used inunderwater prospecting it is necessary that means be available to,operate the clamping mechanism remotely.

The principal object of the present invention is the provision of aclamping means fora system of the type described which is simple,positive in action, and remotely operated.

An additional object of the present invention is the provision in aclamping system of the type referred to of means for positivelypreventing any adhesion of the mass to the clamping members when thelatter are released. This is an important feature because in suchsystems the movement of the mass is slight and accordingly the spacebetween the mass and the clamping members when the latter are inunclamped position is quite small. Under these circumstances when theclamp is operated to release the mass there is a tendency for the massto cling to the clamping members.

In accordance with my invention electrical motor means are employed torotate a screw which is operative to clamp or unclamp the mass of amoving system. A particular feature of my invention is the use of afriction clutch to couple the motor to the rotatable screw. By virtue ofthis provision when the clamped or unclamped position of the screw isreached the clutch will slip sufiiciently to release any undue tensionon the parts, while at the same time the added current required to drivethe motor will indicate that the mass is either clamped or unclamped.

My invention will be more fully understood from the following detaileddescription of the accompanying drawing in which an embodiment of myinvention is shown in elevation, partly in cross-sectional detail. Theembodiment shown relates to a gravity meter. Referring to the drawingthe numeral 30 designates a water-tight housing which contains thegravity meter to permit lowering of the meter to the bottom of a body ofwater. Fixed to the bottom of the housing 30 is a standard 2 at the topof which is a cross member 3 having an upwardly inclined portion 4 atthe end of which is carried a plate 5 having a vertical sectionsubstantially corresponding to 3 sides of an octagon with one of thesesides in a horizontal position. Through each of the inclined sides ofthe octagon is screwed a pair of screws 6 spaced in symmetrical positionto each other. Pivoted on the standardz is a bar I having one of itsends extending beneath the screws 6 and having its other end extendingin the other direction from the pivot in such a way as to bear againstan adjusting screw 8 screwed into the cross member 3.

The mass which is to be clamped is designated by numeral 9 and isarranged between the screws 6 and the bar 1 in such a way that the bar 1can contact it symmetrically with respect to the screws 6. Furtherdetails of the gravity meter are not included herein as they form nopart of the present invention. As may be seen from the drawing, theadjusting screw 8 is arranged for release of bar I by rotationcounter-clockwise, and is provided with a thread I 6 of steep pitch sothat a small rotative movement results in a relatively long longitudinalmovement. The thread is conveniently chosen so that one half revolutionof the screw 8 will be sufiicient to completely clamp or unclamp themass 9. Fixed to the screw 8 are two extensions l8, apart, both adaptedto contact lug [9, one at the clamped position of the bar 1 and theother when the mass 9 is completely unclamped by the same bar 1. Contact of the extension l8 and the lug I9 will cor- .respond in oneposition to the unclamped position of the bar I and will correspond inthe other position to the clamped position of the bar 1.

Extending from the end of the mass 9 is a pin or lug l3. This pin may bethreaded into the mass 9 or may be suitably clamped to the mass. Itextends outwardly from the mass for a small distance, for example abouta quarter of an inch. Horizontally extending from the standard 2 are tworesilient spring wires 2! and 22. These wires are so positioned thatwhen the mass 9 is unclamped no contact is made with the pin l3. In theclamped position, however, pin I3 is caused to press against the upperwire 2| exerting a flexing force on the wire. On release of the clampingmechanism, therefore, the wire exerts a positive force on the pin 13 andthe mass 9, forcing the mass free from the upper clamping members toprevent its adhering thereto. Similarly, release of the clampingmechanism permitting the mass 9 to drop downwardly away from the upperclamp causes the pin I3 to contact the lower wire 22 which exerts apositive upward push to free the mass 9 in the event it tends to adhereto the lower clamping bar 1.

Positioned in the housing above the gravity meter is a D. C. motor 35.This motor and the associated parts to be described, may conveniently bemounted to a plate 36 which may serve as a cover for the gravity meter.The motor 35 is suitably geared to turn at a slow rate of speed; a speedof approximately R. P. M. is suitable. Attached to the shaft of themotor is a conical drive 31 which contacts a similar conical drive 39which is positioned onthe shaft I4. Contact between the conical drivesis maintained by the pressure exerted by the fiat spring 39 which bearsagainst the end of the shaft 4|]. The shaft 40 is coupled to therotatable screw 8 through a socket joint 4| which may be of the typeshown. Longitudinal movement of the screw 8 as it is rotated isaccommodated within the socket 4| without altering the position of theconical drive 38. A suitable bearing 42 is employed to support the shaft40 as It passes through the metal plate 35. Insulated electricalconductors for the operation of the motor 35 are carried to the surfaceof the water through the packing joint 45 of the housing 39. Positionedremotely, for control purposes, is a source of voltage 45, an ammeter41, and a double throw switch 48. The electrical conductors from themotor are connected to four of the poles of the double throw switch sothat the switch acts as a reversing switch. The central elements of theswitch 48 are connected to the other side of the switch will be used forclamping the mechanism. On closing the switch to the unclamping positionat a time when the mechanism is clamped, the motor will be caused torotate in such a direction as to permit the screw 8 to release theclamping mechanism. Rotation of the screw 8 will be continued until theextension [8 has contacted the lug I9. At this instant,'the clutchmembers 31 and 38 will begin to slip on each other causing an increasein the current drain of the motor. This will be indicated as a surge ofcurrent on the ammeter 41 and will instruct the operator that thedesired operation has been completed and the switch 48 may then beopened. Similarly, when it is desired to clamp the mechanism the switch48 will be thrown in the opposite position, causing the motor to rotatein a reverse direction until the clamping mechanism is closed. Completeclosure of the clamping mechanism will again be indicated by a surge ofcurrent responsive to the slipping of the clutch members. The conicalclutch members may be constructed of any desired material. For example,they may be made of wood, plastic, leather or metal. However, it ispreferred that one of the conical drives be composed of leather, or beleather covered, while the other drive is preferably a metallic surfacewhich has been knurled.

Having now fully described my invention, I claim-- A remotely controlledclamping device for a force measuring instrument including aforceresponsive element capable of suspension for response to saidforce, which comprises a first clamping member carrying a plurality ofclamping points, and a second clamping member carrying at least oneclamping point arranged symmetrically in respect to said plurality ofclamping points, said plurality of clamping points and said single pointbeing arranged on opposite sides of a portion of said force responsiveelement, at least one of said clamping members being movable withrespect to the other clamping member so as to place saidforce-responsive element in a clamped position and in a non-clamped ornormal operative position, a pin-like projection on saidforce-responsive element, a pair of resilient wires held by saidinstrument on either side of said projection, one of said resilientwires engaging said projection when said force-responsive element is ina clamped position, the other of said resilient wires engaging saidprojection when said force-responsive element travels beyond its normaloperative position in a direction away from said first named resilientwire, both of said wires being free of said projection when saidforce-responsive element is in its normal operative position, rotatablemeans for adjusting the relative positions of said clamping members soas to place them in clamping and non-clamping positions as desired, anelectric motor having a 'rotatable shaft, friction clutch means couplingsaid rotatable shaft to said rotatable adjusting means, and anelectrical circuit feeding said motor and provided with an ammeterpositioned in said circuit, whereby slippage of said clutch will beindicated by increased current readings of said ammeter.

HERBERT E. OWEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,449,458 Sutermeister Mar. 27,1923 1,876,658 Fox Sept. 1932 1,979,340 Norman Nov. 6, 1934 2,349,404Blair et al. May 23, 1944 2,384,739 Hasbrook Sept. 11, 1945

